Electrolytic lightning-arrester with gap and blow-out.



Patented Sept. 26, 1911.

Fig. 2.

B. E. F. OREIGHTON. ELECTROLYTIC LIGHTNING ARRESTBR WITH GAP AND BLOW-OUT.

APPLICATION FILED SBPT.2,1908.

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o u m n.v mum T we. F mm H mm Witnesses j./ 1

/ WAMM.

UNITED STATES PATENT OFFICE.

ELMEB E. I. CREIGHTON, F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

l ELECTROLYTIC LIGHTNING-ARRlESTER WITH GA]? AND BLOW-OUT.

Specification of Letters Patent.

Patented Sept. 26, .1911.

Application filed September 2, 1908. Serial No. 451,302.

To all whom it may concern:

Be it known that I ELMnn E. F. OREIGH- 'I'ON, a. citizenof the United States, residing at Schenectady, county of Schenectad State of New ork, have invented certain 'new and useful Improvements in Electro- 1 tie Lightning-Arresters Tvith Gaps and 1 low-Outs, of which the following is a.

, specification. This invention relates to devices for protectin alternating current transmission lines om the destructive effects of lightning, either transitory or continua-l, and it has es ecial reference to arresters of the 16 electrolytic type. These arresters are usually placed. in series with a spark-gap of the horn type,- and it is foundthat if the gap is set at the lowest value at which a destructive discharge is likely to occur, the s ark or are may persist,refusing to rise on the horns. 0 present invention is designed to remedy this trouble, and it consists in shunting an aluminum cell across an eleetromagnet in series with the gap, the miignet being so located with reference to the gap that its field. will blow. out the are.

- The cell permits the high frequency light- -ning dischargeto pass through it, thereby protecting the windings net. But the following low frequency dynamic current is forced to flow through and energize the magnet.

In the accompanying drawing, Figure 1 shows diagrammatically an electrolytic arrester in series with a spark-gap having a blow-out magnet in shunt to a single'aluminum'cell; Fig. 1 shows the horns at the gap, andFig. 2 is another diagram showing means for magnifying-the current in the electromagnet.

The line I, which is a conductor carrying an alternating current, is connected to ground at 2 by a circuit 3, in which is ineluded an electrolytic lightning arrcster 4 in series with a spark-gap 5 having horns The arrester is preferably composed of a tier of aluminum cups or cells 7 containingan electrolyte and immersed in an o1 l- 'thn An electromagnet I; is inserted 1n 80 the crcuit betwegn the arregter 4 and the s a If. 'a 5, Sui magnet eing so positiimhd ith reference to the gap that its ma htidfield is transverseto the horns of sin p. In shunt to said electroma net is 56 conne .a device responsive to big fredepends of the, electromagquency currents only. In Fig. 1 this device is shown as a single cell 10 containing a volume of electrolyte and two aluminum electrodes 11.

The drop in potential across the magnet upon the resistance of the cell 10, which at normal potential is high, but for potentials above the normal it is low so-that the impedance to the lightning discharge is sensibly m'Z. KTiischarge of lightning across the spark-gap will, therefore, be taken by the cell. the self-induction of the electromagnet preventing it from being traversed by such a current. on the low-frequency dynamic current follows through and clevclops 'an arc across the gap, the cell c poses the passage of said current and t e greater portion is shunted through the electromagnet, generating a. field of force which at once displaces the are. In other words, the currentu'n the electromagnet depends directly on the potential across the magnet and inversely on the frequency, while the current in the shunting cell depends directly on the potential across the cell and. also directly on the frequency.

he arrangement shown in Fig. 2 signed to magnify the current in the electromugnct. An element; having capacity, such as an aluminum cell 12, is connecfcd in series with the olcctromagnet, the capacity being calculated to neutralize or almostneutralize the inductance of the electromaguct at generator frequency. Two shunting cells 10 are used, connected in series, and allowing a free discharge of high-frequency currents and high potentials onl In this arrangement, as in Fig. 1, the higli frequency discharge passes freely through the shunting cells 10, but the low-frequency is dedyna mic current is shunted through the electromagnet, creating a magnetic field which blows out the are at the spark-gap. Since the self-inductance of the magnet is substantially balancedby the capacity of the cell 12 at generator frequency, the resistance of the magnet circuit follows Ohms law, and as the ohmic resistance is not high the current will be greater than in Fig. 1.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. A protective device for electric circuits comprising a discharge gap, an inductive device mounted to form amagnetic blowout for said gap and in series with said device a condenser proportioned to balance the self inductance of saiddevioe at the normal fre' queni of the circuit to be protected.

2. protective device for'electric circuits comprising a discharge gap, an electromagnet mounted to form a magnetic blowout for said ap, and an electrolytic condenser connecte in series with said elcctromagnct and proportioned to have suflicient ca acity to balance the self inductance of said electromagnet at the normal frequency of the circuit to be protected.

3. In a protective device, a discharge path comprising a spark gap, and means in series with said gap forming a discharge path responsive to oscillations of abnormal frequency and potential, of an electromagnetic blowout device for said gap and connected in series with said ap, and a condenser connected in series with said'devioe and in shunt to said means, said condenser being proportioned to balance the self inductance of said inductive device at the normal frequency of the circuit to be protected.

4. A protective device comprising electrodes separated to form a spark gap, an electromagnet connected in series with said electrodes and mounted to form an electro- .magnetic blow-out for said gap, and means connected to said electroma net for substantially balancing the self-in uctance of said magnet.

5. The combination with a co'nductor of an alternating current system, of a protective device comprising electrodes separated to form a spark gap, one of said electrodes being connected to said conductor, an electromagn'etic blow-out for said gap connected in series with said electrodes, and a condenser connected in series with said electromagnetic blow-out and proportioned to balance the self-inductancc of said electromagnetic blow-out at the normal frequency of the a current on said conductor.

6. The combination with a conductor of an alternating current system, of electrodes separated" to form a spark gap, one of said electrodes being connected to said conductor,

an electromagnetic blow-out for said gap connected in series with said electrodes, and an aluminum cell in series with said electromagnetic blow out and havin capacity to balance the self inductance 0 said electromagnetic bloW-out at normal frequency of the current 'on said conductor.

7. A protective device comprising an eleccell, of electrodes in series'therewith and 1parated to form a spark gap, an electromagnetic blow-out for said gap in series with said electrodes, a condenser connected inserice with said electromagnetic blow-out, and a shunt responsive only to high frequency current and to abnormally connected in series with said spark gap and in parallel to said electromagnetic blow-out an said condenser.

trollytic cell, electrodes connected in series" hlgh potential In witness whereof, I have hereunto set my hand this 31st day of August, 1908. ELMER E. F. CREIGHTON.

Witnesses:

BENJAMIN B. HULL, MARGARET 'E. WOOLLEY. 

